I was once told that anything that I used on my roses, I could and should use on my orchids...and at the same strengh. I guess if I lived in England or Germany, I would experiment, ( like I always do, LOL! )after all, orchids live & die just like any other plants. And, I certainly don't have ALL THE ANSWERS...I recently had a fungus problem, and asked this group "what" to use. They said to get some Daconil. I got it, used it, and now the mold/fungus is back again. Guess we all have to do the best we can...Betty in Texas :-)